package com.itheima.controller;

import com.itheima.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.UUID;

@Slf4j
@RequestMapping("/common")
@RestController
public class CommonController {
    @Value ("${reggie.path}")
    private String basePath;
    @PostMapping("/upload")
    /*文件上传*/
   //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
    public R<String> upload(MultipartFile file) throws Exception{
        //拿到原始的文件名称
        String fileName = file.getOriginalFilename();
        //拿到.jpg或者.png
        String lastName = fileName.substring(fileName.lastIndexOf("."));
        //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String newFileName = UUID.randomUUID()+ lastName;
        //创建一个目录对象
        File dir=new File (basePath);
        //如果目录不存在就创建
        if (!dir.exists ()) {
            dir.mkdirs ();
        }
        //将文件进行拷贝
        file.transferTo(new File (basePath+newFileName));
        return R.success(newFileName);
    }
    /*文件下载*/
    @GetMapping("/download")
    //前端页面/common/download？name=
    public void download(String name, HttpServletResponse response) throws IOException {
        //输入流，通过输入流读取文件内容
        FileInputStream fs=new FileInputStream (new File (basePath + name));
        //输出流，通过输出流将文件写回浏览器
        ServletOutputStream os=response.getOutputStream ();
        //类型为图片文件
        response.setContentType("image/jpeg");
         int len;
        byte[] bytes=new byte[1024];
        while ((len=fs.read (bytes))!=-1){
            os.write (bytes,0,len);
            os.flush ();
        }
        os.close ();
        fs.close ();

    }
}
